package edu.spec.chenli.Servlet;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

public class DbDao {
    private Connection conn;
    private String driver;
    private String url;
    private String username;
    private String password;
    public DbDao()
    {

    }
    public DbDao(String driver, String url, String username, String password){
        this.driver=driver;
        this.url=url;
        this.username=username;
        this.password=password;
    }

    public String getDriver() {
        return driver;
    }

    public void setDriver(String driver) {
        this.driver = driver;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
    //获取数据库连接
    public  Connection getConnection() throws  Exception{
        if (conn==null){
            Class.forName(this.driver);
            conn= DriverManager.getConnection(url,username,this.password);
        }
        return  conn;
    }
    public boolean insert(String sql,Object...args)throws  Exception{
        PreparedStatement pstmt=getConnection().prepareStatement(sql);
        for(int i=0;i<args.length;i++){
            pstmt.setObject(i+1,args[i]);
        }
        if(pstmt.executeUpdate()!=1){
            return  false;
        }
        return  true;
    }
    public ResultSet query(String sql,Object...args)throws  Exception{
        PreparedStatement pstmt=getConnection().prepareStatement(sql);
        for(int i=0;i<args.length;i++){
            pstmt.setObject(i+1,args[i]);
        }
        return  pstmt.executeQuery();
    }
     public void modify(String sql,Object...args)throws  Exception{
        PreparedStatement pstmt=getConnection().prepareStatement(sql);
         for(int i=0;i<args.length;i++){
             pstmt.setObject(i+1,args[i]);
         }
         pstmt.executeUpdate();
         pstmt.close();
     }
     public void  closeConn()throws  Exception{
        if(conn!=null && conn.isClosed()){
            conn.close();
        }
     }


}
